How to block posts in parent forum but allow in sub forums?

[RocketFoot]

Thanks!  That worked but I have another small problem!  I have changed my forum icons from gif to png but now the category parent forum I just made has a gif forum icon.  How can I change that to png to match the rest of my custom icons?

Scroll half way down to see what I mean!
http://www.7173mustangs.com/index.php

Also, do you know how to add banner images to the right of the forum name and descriptions?